It is known to apply certain nitrogenous compounds on textiles as antistatic agents. In U.S. Pat. No. 2,897,170 of Gruber, there is disclosed for this purpose the use of quaternary ammonium salts having polyoxyalkylene side chains. However, the system of U.S. Pat. No. 2,897,170 is not wash durable and the treated product does not possess satisfactory antistatic properties after repeated washings. In U.S. Pat. No. 3,925,462 of Graff, there is disclosed a wash durable antistatic agent utilizing quaternary ammonium salts having polyoxyalkylene side chains. However, the system is quite complex and involves reaction of the quaternary salts with an aromatic polyisocyanate and a thermally reversible blocking agent prior to application to the fabric, as well as a heat-curing step of the treated fabric.
In U.S. Pat. Nos. 3,595,813 and 3,749,597 of Hartgrove, there are disclosed wash durable antistatic finishes obtained by reacting a crosslinking agent such as a melamine formaldehyde derivative with certain nitrogen-containing polyoxyalkylene materials. The preferred polyoxyalkylene materials are polymers having recurring units of the formula: ##STR1## While this finish is satisfactory for many uses, it can cause significant yellowing of white fabrics and discoloring of light colored fabrics. Additionally, this finish has an adverse effect on the tactile aesthetics, such as hand, of some types of fabric, particularly lightweight tricot fabrics.
The problem of fabric discoloration is due, at least in part, to the presence of nitrogen in the antistatic component of the finish, which, upon exposure to atmospheric oxygen, pollutants in the air, and other various chemicals, can chemically react to form highly colored products. Moreover, the antistatic properties of such a finish are proportional to the amount of nitrogen present. In order to assure that satisfactory antistatic properties will be obtained on the substrate fabric after multiple launderings, a considerable excess of the antistatic component must be applied to the fabric initially, since much of the finish is lost in laundering or in wear. The high add-ons required to achieve satisfactory durable antistatic properties have an adverse effect on fabric hand, and also intensify the problem of fabric discoloration.